Sound-amplifier



J. MERSMAN.

SOUND AMPLIFIER. APPLICATION FILED MAY I2, 1919.

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4 @Menbpz Z 70 fiat vi A mman UNITED JosErH MERSMAN, or OTTAWA, OHIO.

OFFICE- so nn-ArirLrFIEn.

To all whom it may concern:

Be it known that I, JOSEPH Melisa/IAN, a

citizen of the United States, residing at reproducing machine without affecting the purity of tone and without causing those harsh and blasting sounds which are sometimes produced to be magnified bythe amplifier, and which at the same time will resonate in accord with the musical sounds being reproduced in a manner to enhance the quality of the tone.

A further object of the invention is to provide an amplifier having the above quali- .fications which is capable of being embodied in the form of a soscalled concealed horn or amplifier for use in existing types of reproducing machines without change in the structure of other parts of the machine.

Various other objects of my invention will be apparent from a perusal of the following specification and the drawings accompanying the same.

My invention is illustrated in the accompanying drawings in which'- Figure 1 is a front elevation.

Fig. 2 is a top plan view.

Fig. 3 is aside elevation with the near side of the horn removed to show the interior parts.

Referring to the drawings in detail, it Wlll be seen that the horn consists of the top and side walls 1, 2 3 and .4 which taper and approach each other toward the back to form a rectangular funnel having the front portion braced by the frame 5, the rear portion connecting in any suitable manner with the usual elbow or throat leading to the tone arm not shown.

Intermediate the length of the horn and bearing against the upper and lower walls 1 and 2 is a brace 6 and a short distance in front of this brace I provide a tightening rod 7 arranged to be tensioned by means of Specification of I etters' Patent.

Patented June 22,1920.

'App lication filed May-12,1919. Serial No. 296,517.

a suitable turn buckle S oonnected intermediate its ends, the ends of the rod passing through the upper and lower walls and terminating in headed portions 9 and 10 which bear inwardly on the walls through bridges 11 and 12 respectively. The feet of the bridges 11 and 12 and the feet 13 of the central brace'S bear on the upper and lower walls of the amplifier through pads 14 and 15 respectively, of felt or other suitable material. By tightening the rod 17 the top and bottom walls are put under tension by the inward pressure of the bridges 11 and 12 and the outward pressure of the middle and front braces 6 and 5 and the side walls 3 and 4. 'Each of the side walls 3 and 4 is arranged to be put under lateral tension by means'of tightening rods 16 and 17 which bear inwardly on the central portion of the side walls 3 and 4 through bridges 18 and 19 and outwardly on the upper and lower edges of the side walls through the inner bridges 20 and 21. The tightening rods 16 and 17 bear against their respective outer bridges through heads 22 and against their inner bridges through the wing nuts 23 which serve as means for varying the pull or tension on their respective rods 16 and 17.

Suitable pads 24 are placed between the side bridges 18 and 19 and the sidewalls. It will be seen that by tightening the wing nuts 23 the side walls are tensi'oned in wardly at the center and are made to bear against the inside bridges 20 and 21 and the sides of the front brace 5. Thus with the structure above described, all four sides of the amplifier may be put under tension and the tension. adjusted to cause the horn to so resonate in accordance with the sounds be ing reproduced as to produce the most desirable quality of tone. As the different parts of the amplifier are all tensioned inwardly and against each other and the various braces, there is no lost motion or loose play between them. Also the sides being tensioned are given a surface or skin tension which makes for increased resiliency.

It is to be noted that while I have herein described and shown one specific embodiment of my invention, for the purpose of disclosure, it is to be understood that I do not limit myself to such specific embodi- V ment but contemplate all such reversals,

variants and modifications as fairly fall within thefscope of the appended claims.

Having thus described my invention what I claim and desire to secure by Letters Patent is:

1. A sound amplifier for talking machines comprising top, bottom and side walls inclosing a tapering chamber, With non-resonant bridge tensioning means applied to said Walls, each bridge having end supports engaging a Wall to exert a thrust thereon at separated points thereof, and intermediate means to draw the same Wall against the said end supp0rts,'all of said engaging parts being insulated as to sound vibration from the said Walls.

2. A sound amplifier as claimed in claim 1 having intermediate tensioning means composed of rods engaging supplemental bridges engaging the Walls of the amplifier on opposite sides from the main bridges and similarly insulated therefrom as to sound.

In testimony whereof I affix my signature.

JOSEPH MERSMAN. 

